Locking dock with adjustable bumpers

ABSTRACT

An adjustable bumper system for use at a loading dock which has a dock leveler having a deck pivotally mounted to a portion of the dock. The dock leveler has a lip pivotally attached to one end of said deck. The bumper system has a pair of bumpers each mounted to the end of the deck. The bumpers move with the deck to engage the rear of a vehicle that has backed into position for dock operations. Alternatively, the dock bumpers are mounted to a support member and are positionable between two different vertical positions. The dock bumpers project outward from the dock beyond the pendent lip and are adjustable to engage the rear of vehicles having different heights.

CROSS REFERENCE TO RELATED PATENTS AND APPLICATIONS

[0001] This patent application is related to U.S. Pat. No. 6,006,389, entitled “Loading Dock with Adjustable Bumpers” and to U.S. Pat. No. 5,881,414, also titled “Loading Dock with Adjustable Bumpers”, both having the same inventor as this application and both commonly assigned with this application.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to loading dock equipment and in particular to a dock structure having bumpers that are vertically adjustable to accommodate vehicles of different sizes.

[0004] 2. Prior Art

[0005] Most loading docks are designed for standard truck trailers which typically have a bed height of 48 to 52 inches. Many new “high-cube” trailers have a bed height of 32 to 36 inches. The difficulty is that dock bumpers placed high enough for a standard trailer will impede access to low trailers. Conversely, bumpers placed for the low trailers will allow standard trailers to pass over and impact the building. There are several conventional solutions to accommodate both low and standard height trailers but all involve compromises that impede effective dock operations.

[0006] The simple solution is to have separate docks, each having the proper height for the trailer, but this increases cost of a dock installation and reduces the flexibility of a single dock to handle various trailers. As a consequence the dock may be unoccupied for periods of time because the trailers do not match the configuration.

[0007] Another solution is to use wheel riser ramps or hydraulic truck levelers mounted on the driveway. However, this solution interferes with the ability of vehicle restraints to engage the ICC bar of the low trailer when it is raised to dock height, and also interferes with snow removal in northern climates. Some low trailer applications can be serviced by using long dock levelers with extended below dock range. However, most dock levelers are limited to 7 feet width as a wider leveler would not allow sufficient space at each side to mount the bumpers to engage the trailer. Also, if the cargo to be loaded is the full width of the trailer, it will not pass between the sides of the leveler pit when the leveler is below the dock floor. It is also expensive to install.

[0008] U.S. Pat. No. 4,420,849 proposes the use of a bumper that folds away under the dock leveler and is pivoted into position as required when the leveler is actuated. However, this device cannot be used when the deck is operated in a below dock operation with the leveler depressed. Moreover, when stored it impedes cleaning operations under the deck.

[0009] The inventor here has also proposed a solution in U.S. Pat. No. 5,881,414 using beams carrying bumpers that move independently of the deck yet allow a full range of movement and adjustment. An alternative arrangement mounts the bumpers on vertically extending members mounted to the dock face to facilitate vertical adjustment as a function of deck height. These systems both provide an effective solution to providing a bumper system for a loading dock that accommodates trucks with beds of differing height but have cost and complexity implications associated with their implementation.

SUMMARY OF INVENTION

[0010] Given the current state of dock implementation it is therefore an object of this invention to provide for an improved low cost dock structure that is fully functional for trailers of differing configurations.

[0011] It is a further object of this invention to provide a system of adjustable height bumpers whose position can be changed to match the height of trailers to be parked at the dock.

[0012] A further object of this invention is to provide an adjustable bumper that is low in cost and whose installation and use is compatible with standard loading dock equipment but using standard dock loading equipment.

[0013] These and other objects of this invention are accomplished by a loading dock which allows full access to both standard height and low trailers. This invention uses a standard height dock and a dock leveler carrying bumpers to accommodate both low and standard height transport vehicles. The bumpers may be fixed or mounted on the deck face for adjustment.

[0014] In accordance with a first embodiment of this invention, the bumpers are always positioned relative to the truck bed by virtue of riding with the deck of the dock leveler. Thus, when a standard height vehicle is at the dock, the top of the bumper is level with the dock floor and the bumpers are at the normal dock height to cushion the truck against the deck. When a low vehicle is at the dock, the deck is lowered and this places the bumpers at the lower height and to allow the full width of the door to be clear for wide cargo. In this embodiment the bumpers are fixed to the front of the deck.

[0015] In accordance with a second embodiment of the invention, the bumpers are mounted on a track that in turn is mounted to the front of the deck. This provides variable vertical adjustment independent of the position of the deck. The bumpers, mounted to the track, are moved vertically into position by an operating cylinder, ratchet, manual crank or the like.

[0016] This invention will be described in greater detail by referring to the drawing and the description of the preferred embodiment that follows.

BRIEF DESCRIPTION OF THE DRAWING

[0017]FIG. 1 is a perspective view of a preferred embodiment of this invention with the leveler deck and dock bumpers at floor level for standard height transport vehicles;

[0018]FIG. 2 is a perspective view of the dock with deck and the bumpers lowered for low transport vehicles and the leveler with the lip of the dock leveler extended to rest on the bed of the transport vehicle;

[0019]FIG. 3 is a perspective view of the dock with the bumpers lowered for low transport vehicles and the leveler at the lowest position with the door closed and resting on the leveler with the top of the bumper support beams to seal the door opening;

[0020]FIG. 4 is a side view of a second preferred embodiment of the bumper support system illustrating a mounting mechanism which permits the bumper to be raised into position independently of the position of the deck for end loading operations; and

[0021]FIG. 5 is a second side view of the second preferred embodiment of the bumper support system of this invention with the lip extended for below dock operations.

DESCRIPTION OF THE FIRST PREFERRED EMBODIMENT

[0022] Referring now to FIG. 1, the loading dock is shown with a driveway approach 1, a dock face 2, a wall 3 (partially cut away), and a dock floor 4 with a recessed pit 5. The pit 5 may have a width the same as or be wider than a conventional dock leveler pit to accept a dock leveler 10 and two bumpers 26. The dock leveler 10 has a conventional hinged deck assembly 11 and hinged lip assembly 12. The bumper assembly 26 in the case of a standard width dock leveler is mounted adjacent to the lip 12. The bumpers are mounted to the end of the deck and preferably at a height such that they are flush with the deck so that any inadvertent movement of a fork lift truck toward the edge of the deck will not damage them.

[0023] The lip does not extend the full width of the deck but rather is cut away at the ends to allow the bumpers to be mounted. The hinge tube for the lip thus does not extend across the full width of the deck. Typically the width of the lip is slightly less than the width of a truck bed and thus defines the area of movement of a fork lift truck into and out of a vehicle during loading operations. Preferably the deck will be made wider than the truck bed to allow room for a standard width lip between the bumpers. Alternatively, the deck may be a standard width, and the lip will thus be cut down on the sides to allow placement of the bumpers.

[0024] As shown in FIG. 1, an optional stop bar 30 is attached to each side of the front of the pit 5 and supports the front of the deck when it is in the lowered position. This will be explained relative to FIG. 3. FIG. 1 also illustrates the use of conventional lip keepers 20 to support the deck 12 in the horizontal cross-traffic position.

[0025] The operation of the system in accordance with this first preferred embodiment will now be described. FIG. 1 shows the bumper assemblies 26 and the dock leveler 10 stored at floor level. When the deck 10 is raised to extend the lip and then lowered to the bed of a transport vehicle 50, the bumpers will be adjacent to but beneath the lip to engage the vehicle and prevent rearward movement into the deck. As the suspension of the vehicle 50 moves vertically in response to being loaded or unloaded, the leveler follows this movement and accordingly the bumpers remain in position aligned with the bed of the vehicle.

[0026] When a low truck is to be loaded or unloaded, as illustrated in FIG. 2, the leveler 10 with the lip 12 of the dock leveler 10 is extended and resting on the bed of a transport vehicle 50. The top of the deck of the dock leveler 10 is below that of the loading dock. In this position the dock is still protected from damage from a low trailer, since as illustrated, the rear of the trailer will impact the bumper 26 and not the dock face.

[0027] While not illustrated it is apparent that the system will still function with the leveler at the lowest position for “end loading” or removing cargo from the end of the vehicle without the lip extended. That is, the lip can be lowered to the state illustrated in FIG. 1, but the protrusion of the bumpers 26 still protects the truck.

[0028]FIG. 3 illustrates the loading dock door 55 in a lowered state onto the leveler which is also lowered. This position is to be used primarily for low trucks. The stop bar 30 supports the leveler since the lip 12 is not constrained by the lip keepers. The stop bar also acts as a barrier sealing of the underside of the support beams, thus providing a degree of security and environmental protection. In this embodiment the stop bar 30 is mounted on the pit floor. It could be carried by the leveler 10 as a leg.

[0029] This invention is not limited to the specific configuration described above. While the dock shown is for standard height vehicles, this design could be equally as effective for a dock built at a lower height. The lowered position of the bumpers would then be at floor level and the raised position would be above floor level. Similarly, a more complex control system could allow the bumpers to be supported at more than two positions, as described with respect to the second preferred embodiment.

DESCRIPTION OF THE SECOND PREFERRED EMBODIMENT

[0030] Referring now to FIGS. 4 and 5, a second preferred embodiment is illustrated. The loading dock is shown similar to FIG. 1. Instead of having the bumper mounted directly to the front plate 24 of the leveler frame, the bumper is mounted on a frame 32 for vertical movement. The frame itself extends below the deck as illustrated in FIG. 5 and is carried by the deck. The bumper is therefore free to be positioned independently of the deck position.

[0031]FIGS. 4 and 5 are side elevation view illustrating the position of the bumper to block a low truck in two different modes of operation. In FIG. 4 an end loading operation is depicted with the lip 12 retracted but with the deck in the horizontal position. The bumpers 26 are raised to block the truck. Since the useable width of the deck 10 is defined by the width of the lip 12, the fact that the bumpers on the lateral sides of the deck are raised is of no consequence because they are not in the way of the operator during this last, typically manual, stage of loading the truck to the very rear of the cargo deck.

[0032] In FIG. 5 the lip is still extended to allow fork lift operations. The bumpers 26 have been lowered on the track 32 to still engage the rear of the vehicle but will not impede movement of the fork lift. The bumpers 26 are thus positionable on the track 32 to match the loading condition encountered.

[0033] In the case of the second preferred embodiment the bumpers can be simply mounted on tracks rails on the dock leveler face and slide to positions at different vertical positions depending on the configuration of the truck. Simple mechanical stops can be employed and the bumpers positioned by hand. Alternatively, motive sources such as electric motors or mechanical arrangements such as ratchets may be employed. 

I claim:
 1. A system for use at a loading dock comprising: a dock leveler having a deck pivotally mounted to a portion of said dock, said dock leveler having a lip pivotally attached to one end of said deck, a dock bumper mounted to said deck, facing outward and beyond said lip when said lip is in a pendent position.
 2. The system of claim 1 further comprising a frame mounted to said deck to support bumper and allow said bumper to be moved relative to said deck.
 3. The system of claim 2 wherein said support is a track attached to said deck and said bumper slides on said track.
 4. The system of claim 1 further comprising a stop to engage the bottom of said bumper.
 5. The system of claim 1 further comprising a second bumper, wherein said bumpers are mounted at corners of said deck and said lip is mounted for pivotable movement between said bumpers.
 6. The system of claim 1 further comprising a track mounted to the end of said deck, said track extending below said deck to allow said bumper to be positioned within a range of movement extending from above said deck to below said deck.
 7. The system of claim 6 further comprising a second track mounted to the end of said deck and, a second dock bumper mounted to said second track member and positionable between two different vertical positions, whereby each of said bumpers is independently adjustable relative to said deck.
 8. The system of claim 7 wherein said first and second tracks comprise beams mounted in parallel and said bumpers project outward from said dock at substantially the same distance.
 9. The bumper system of claim 1 wherein said bumper is mounted on the end of said deck flush with said deck surface.
 10. The bumper system of claim 9 further comprising a second bumper mounted on said deck, each of said bumpers projecting outward beyond said lip when said lip is in a pendant position. 